Electrical discharge device



- Oct, 1, 1929. L. c. BILLOTTE ET AL ELECTRICAL DISCHARGE DEVICE Original Filed Dec. 20. 1926 5 l R n 09. N un R 0 0 T N qm wm B A C d y l mw m LE Patented Oct. 1, 1929 UNITED sTATEs PATENT OFFICE.

LOUIS 0. humour ELECTRICAL DISCHARGE DEVICE Original application filed December 20, 1926, Serial No. 155,842. Divided and this application filed December 8, 1927.

This invention relates to electrical discharge devices of the type employing ionized gas, and more particularly to rectifiers for alternating current.

The present application is a division of our copending application Serial No. 155,842, filed December 20, 1926, for Electrical discharge devices.

Some of the objects of the present invention are to simplify the construction of electrical discharge devices of the gas filled type; to increase the efficiency of said devices; to increase the reliability and uniformity of their operation; to reduce the time required for ageing said devices; to insure uniform operation; to lower the impedance of devices of the kind referred to; and generally to improve the construction of devices of the kind referred to.

In accordance with one aspect of the present invention, an envelope or vessel contains anode and cathode electrodes immersed in an ionizable gas, these electrodes being so designed and arranged that the space current is efiiciently produced and controlled when suitable voltage is applied to the electrodes, and that the device is strong and rugged 111 construction.

When employed as a rectifier, the device may have a cathode, consisting of a thin metallic sheet or plate, positioned laterally over one or more anodes apertures being preferably provided in the cathode opposite the anodes. The cathode is held in fixed relation with respect to the anode or anodes by interfitting with insulating material held in fixed relation with the anode. The construction of the discharge device is simplified and made more rugged by supporting all of the electrodes from a single reentrant stem.

These and other objects and features of the invention will be understood more clearly from the following detailed description in connection with the accompanying drawlng, in which:

Fig. 1 is a vertical section of an electrical discharge device, and Fig. 2 is a plan of the electrode structure.

In Fig. 1 the receptacle, vessel, or tube 1, of glass or other suitable material, contains sleeve by a distance Serial N0. 238,625.

an ionized gas, preferably of the helium group, for example. argon, helium, or neon, or a suitable mixture thereof. The pressure of the gas within the vessel is preferably in the vicinity of two to twenty millimeters of mercury when filled at a temperature in the vicinity of 25 degrees centigrade, but may be somewhat above or below these limits.

A reentrant stem. integral with receptacle 1 and having the press 2, supports two parallel hollow stems or projections 3 integral therewith, one stem being shown in full elevation and the other in section. The stems 3 may be of glass or other suitable electrical insulating material. The insulating sleeve 4, of lava or other suitable refractory insulating material, having its lower end fitting coaxially over .the free end of each stem 3, is provided with a constricted portion 5 forming a ledge resting on the free end of stem 3 and adapted for holding the elongate anode wire 6 coaxially therewith.

The anodes 6 may be of manganese steel, nickel or other suitable material. Each anode has an electron receiving surface 7 at the upper end thereof within the sleeve 4 and spaced inwardly from the upper end of the preferably greater than the mean free path of electrons in the gas in receptacle 1. It will be noted that sleeves 4 extend beyond the ends of the stems or tubes 3 and beyond the ends 7 of anodes 6 and serve to hold the anodes 6 in fixed relationship with each other and with the press 2. An annular space 8 is preferably provided between the upper or free end of anode 6 and the inner wall of sleeve 4, a recess 9 of larger diameter than that of space 8 being provided above the free end of the anode in each sleeve.

A cathode 11, of manganese steel, nickel or other suitable electrical conducting material is preferably in the form of a sheet or plate and, in the modification shown as an example of the invention, the cathode is in the form of a disk. Cathode 11 is positioned laterally over sleeves 4 and anodes 6, and rests on the ends of sleeves 4.. A air .of thimblee or ring shaped recesses 12 t over the free ends of the sleeves, each thimble being coaxial with one of theanodes 6.

' In the modification of the invention shown by way of example, the thimbles are connected by a bridge'13 for constructional reasons, so that the two thimbles may be looked upon as being a single thimble when taken as a whole. Spaced openings or perforations 14 of slightly larger diameter than anodes 6 are provided in cathode 11. Each opening is positioned coaxially over an anode 6, so that the electron receiving portion 7 of each anode is presented to one of the openings in the cathode.

A stay wire 15 sealed into press 2, normally to cathode disk 11, is secured to the disk to hold it from moving axially of anode 6 and sleeves 4 the thimbles 12 serving to hold disk 11 from moving laterally to sleeves 4:, so that perforations 14 are retained in coaxlal or centered relationship with anodes 6. It will be noted that the perforations 14 are positioned centrally 1n disk 11 and are symmetrically disposed thereln, the stay wire 15 being anchored to the center of the disk between perforations 14.

Stay wire 15 is made fast to cathode 11 by securing the wire to a projection 16 from the cathode b spot welding or other sultable means. Tie projection may be formed by a U-shaped channel member 16 secured to cath- ,ode 11 by spot welding or other suitable means at the bottom of the U, the arms of the U being spot welded to opposite sides of the stay wire 15 which pierces a hole in cathode 11 and the bottom of the U-shaped member 16.

This form of construction makes it possible when assembling the electrodes together to make adjustment for any variations in the dimensions of the parts, so that cathode 11 may be placed firmly against the free ends of the sleeves 4 and may be held there by welding the element 16 to wire 15.

The upper surface of cathode 11 1s preferably coated with an active electron emitting substance such, for example, as the oxides of barium or strontium. The edge or flange 17 is turned up around the electron emitting surface of the cathode and serves to reinforce the cathode, particularly during and after baking the cathode at high temperature by the action of a high frequency magnetic field directed axially of the disk.

The described relation of electrode spacings to the mean free path of the electrodes in the gaseous-filling, gives rise to high con ductivity between one of the electrodes 6 and electrode 11 when the electrode 6 is positive with respect to electrode 11 and gives rise to relatively low conductivity or open circuit conditions when the potentials of the elec trodes are reversed. It is thus possible to efficiently rectify alternating current. The rectifier, shown as illustrative of the invention, is adapted for full wave rectification one of the anodes and the corresponding cathode perforation and thimble may be omitted, or the circuit of one anode may be left open in order to provide a rectifier fdf' only one-half of each cycle of an alternating current wave. Furthermore, it is to be understood that the invention is not limited to single phase rectification, or to two-phase rectification wherein the phases are separated by 180 electrical degrees, as in full wave rectification, but the principles disclosed are obviously applicable to rectifiers for a larger number of phases.

It will be noted thatthespaces within the tube in the regions adjacent the anodes 7 inter-communicate near the active or upper surface of the cathode and that the cathode may be looked upon as being an obstruction containing the openings 14 restricting the flow of space current to the upper side of the cathode except through the openings 14. Thimbles or rings 12, interfitting with insulating sleeves 4, cooperate with stay Wire 15 in holding the cathode and anodes in fixed relationshi radially of openings 14, and hold the electrodes in fixed relationship with press 2.

The spacing of the anod s from the cathodes is preferably greate than the mean free path of the gas within which the electrodes are immersed, whereby a low impedance path is produced between the electrodes in the tube 1, although, if desired, these electrodes may be separated by distances less than the mean free path of the gas.

The rugged mounting of the electrodes insures uniform operation of the discharge de- Vice and prevents damage to the device from mechanical shocks during handling of the device. The form of cathode plate 11 has been found particularly suited to heat treatment after assembly, so that the device may be quickly aged. I

It is to be understood that the usual terminals, not shown, may be provided at the base of tube 1 connecting with the electrode leads, so that the base of the tube fits into a socket in well known manner. The principles disclosed herein are not limited to application to rectifiers,but are broadly applicable to various forms of electrical discharge devices employing ionized gas therein.

We claim 1. An electrical discharge device comprising a gas filled vessel containing a plurality of anodes, a cathode plate positioned laterally over said anodes, means for holding said electrodes in predetermined relation, said means including a wire normal to said plate on the same side thereof as said anodes and having one end fast to said vessel, the other end thereof reaching up to said plate, and a U-shaped channel member for securing said plate to said wire, the bottom of said channel member being fast to said plate, the arms of said U being fast to said wire;

2. An electrical discharge device comprising a gas filled vessel containing a plurality of anodes, a cathode plate positioned laterally over said anodes, means for holding said electrodes in predetermined relation, said means including a wire normal to said plate on the same side thereof as said anodes and having one end fast to said vessel, the other end thereof reaching up to said plate and extending through a hole therein, and a U-shaped channel member on the side of said plate opposite to said anodes for securing said plate to said wire, the bottom of said channel member being fast to said plate and having a hole therein pierced by said wire, the arms of said U being fast to said wire.

In witness whereof, we hereunto subscribe our names this 2nd day of December, 1927.

LOUIS O. BILLQTTE. EDWARD LIPSON. 

